postbackup does not works after using HttpUtility.HtmlDecode

Hello

I have strange problem

After using function HttpUtility.HtmlDecode  (see code below) my site stops to works .

It works only at first time then I call function ,but  in the second time the  page is not  responds ,looks like postback is not works any more.

SubGridView_ItLog_Status_SelectedIndexChanged(ByValsenderAsObject,ByValeAsSystem.EventArgs)HandlesGridView_ItLog_Status.SelectedIndexChanged

DimcommentsAsString= GridView_ItLog_Status.SelectedRow.Cells(6).Text

Try

HttpUtility.HtmlDecode(comments).ToString()  

CatchexAsException

EndTry

How can find the source of problem

Thanks